Nitrogen-Doped Porous Carbon Nanospheres Activated under Low ZnCl₂ Aqueous System: An Electrode for Supercapacitor Applications

Abstract

We reported a controlled synthesis method to obtained carbon spheres with tunable geometry under low ZnCl 2 aqueous solution conditions using polytriazine as a precursor. The polytriazine precursor was polymerized by mixing/reaction of 2,6diaminopyridine and formaldehyde in the presence of a diluted ZnCl 2 aqueous system. The obtained nanospheres were then decomposed to adulterate nitrogen porous carbon nanospheres (N-PCNSs) by the decomposition and blistering process at high temperature by degrees. ZnCl 2 worked as a solid-template and played the role of a stabilizing and foaming agent in the reaction. The as-prepared N-PCNSs with controllable spherical geometry, large micro-/mesoporous volume and high nitrogen content (∼8.5 wt %) were employed in electric double-layer capacitors that have a good specific capacitance (636 F/g at 1 A/g) and are long lasting. Besides, the N-PCNS delivered a high energy density of 22.1 Wh/Kg at a power density of 500 W/kg.

ZnCl2 as a “Nitrogen Bank” to Inhibit Nitrogen Loss during the Thermal Conversion of Nitrogen-Containing Carbon Precursors to Nitrogen-Doped Carbon

“…Moreover, the H 3 PO 4 poisoning experiment (see details in Figure S12) demonstrates that the better catalytic activity of N/C ZnCl 2 (than N/C) primarily arises from its higher N-content, especially the Py-N content (rather than carbon defects). These results suggest that the added ZnCl 2 more likely acts as a N-bank to elevate the N-content (especially the Py-N content) rather than as an activating agent (creating pores and carbon defects) in the resultant carbon materials for lowering the ORR overpotential. ,, …”

“…These results suggest that the added ZnCl 2 more likely acts as a N-bank to elevate the N-content (especially the Py-N content) rather than as an activating agent (creating pores and carbon defects) in the resultant carbon materials for lowering the ORR overpotential. 18,24,25 The average electron transfer number (n) of the ORR on N/ C ZnCl 2 was obtained by using the K−L equation (see details in SI). The n is calculated to be around 4.0 (Figure 3b), implying that the N/C ZnCl 2 , like the Pt/C, catalyzes the ORR in a direct 4e − pathway.…”

Simple fabrication of a phosphorus‐doped hierarchical porous carbon via soft‐template method for efficient CO2capture

“…For chemical activation, the most commonly used activators include ZnCl 2 , H 3 PO 4 , NaOH, H 2 SO 4 , KOH, and K 2 CO 3 . They can be used to make carbon materials with high surface areas and suitable porous structures 33–36 . The template method, one of the most widely used synthesis techniques for carbon materials, uses a template to effectively control the pore structure and prepare a material with an orderly structure and uniform pore size.…”

“…They can be used to make carbon materials with high surface areas and suitable porous structures. [33][34][35][36] The template method, one of the most widely used synthesis techniques for carbon materials, uses a template to effectively control the pore structure and prepare a material with an orderly structure and uniform pore size. There are hard and soft template methods.…”

Surface Polymerization and Controlled Pyrolysis: Tailorable Synthesis of Bumpy Hollow Carbon Spheres for Energy Storage

“…Carbon spheres and other nanocarbon materials have shown great potential in the application of energy storage for their excellent electronic conductivity and high specific surface area (SSA), along with stable electrochemistry. − The architectural design of carbon spheres endows them with a number of novel attributes including adjustable particle size distribution, regular geometry, and a refined structure and hence is of significant impact on their electric properties and corresponding electrochemical performances. − Recently, numerous efforts have been dedicated to the engineering of hollow carbon spheres (HCSs) as energy storage electrode materials − because (i) the hollow cavity can provide free space, favoring strain relaxation, as well as accommodation of volume change for electrode materials amid repeated lithium intercalation/deintercalation; and (ii) the thin and porous shells can shorten diffusion distances for both electrons and lithium ions, thus contributing to the improved rate capability. However, low tap density, small SSA, and excessive interior cavity space of the intact hollow structure hinder their application as energy storage electrodes.…”